The present invention relates to a method for generating a digital image of at least a portion of a value document, in particular such a method in which the value document is moved relative to a capture pixel region, and an apparatus for carrying out the method.
Within the framework of the invention value documents are understood as card- or sheet-shaped objects, which represent for example a monetary value or an authorization and which should therefore not be producible at will by unauthorized persons. Hence, they have features that are not easily produced, in particular copied, whose presence is an indication of authenticity, i.e. production by an authorized body. Some important examples for such documents of value are chip cards, coupons, vouchers, checks, shares and in particular bank notes.
For reasons of design, for distinctiveness and for protection against simple falsifications documents of value are typically provided with a graphic design, for example more or less complex patterns and/or representations and/or characters and/or combinations of characters and/or writings. The graphic design can be executed entirely or partially colored and/or black and white and/or in gray scales.
Due to the very great number of documents of value in circulation for example in the case of bank notes, detection by machine or automatic detection of the value documents or detection by machine or automatic detection of the state of the value documents is desirable. For this purpose the value documents can be transported at great speed past optical sensors in corresponding value-document processing apparatus, with the sensors capturing an image of the respective value document during the respective transport. 12
However, it has been found that images captured with high resolution in such apparatus frequently do not have the desired image quality.